1. Field of the Invention
The present invention relates to a reagent system that can be used to detect aldehyde in biological specimens. The invention also relates to production of a test kit utilizing the reagent system, and various applications of the test kit.
2. General Background and State of the Art
Research has shown that the amount of oxygen free radicals present in the body correlates to the degree of exposure to stress, ultraviolet light, and extraneous forms of pollution. It is known that when oxygen free radicals, which are byproducts of metabolic activities, oxidize long chain polyunsaturated fatty acids within the body, aldehydes are released. Different types of aldehydes, including malondialdehyde, 4-Hydroxynonenal, acetaldehyde, 1-propanal, 2-methylpropanal, 2,2-dimethylpropanal, 1-butanal, 1-pentanal, and n-hexanal, are created during this process. Such forms of aldehydes, due to their strong reactivity, cause many health complications by altering the structure of proteins and mutating nucleic acids. Therefore, it is desirable to measure the amount of aldehydes, which may indicate the extent of the presence of oxygen free radicals in the body.
Malondialdehyde is a natural component of urine. Its presence can be detected by using a fuchsin testing kit or a spectrophotometer, fluorometer, HPLC or GC-MS. Reagents of conventional fuchsin based testing kits had to be stored in acidic conditions and tested in acidic environments. For example, U.S. Pat. No. 6,689,617 presents a fuchsin based test kit comprising sodium metabisulfite, distilled water, phosphorus, and fuchsin that uses a reagent of between 1.75-1.93 pH to detect malondialdehyde in urine. In U.S. Pat. No. 6,165,797, another test kit composed of acetic acid, sodium bisulfite, distilled water, phosphorus and distilled water is presented.
Basic fuchsin, which is a purple powder, alters its color relative to the amount of aldehyde present in an acidic environment. The amino group of fuchsin couples with the aldehyde to produce a pink to purple color approximately dependent on the amount of aldehyde present in biological fluids such as blood or urine. Conventional test kits that use basic fuchsin require acidic environments for the color alteration to be executed; thus the accuracy of test results is compromised during the process of combining fuchsin with biological specimen (generally of higher pH), which dilute the concentration of malondialdehyde and cause the reaction process to be dependent on the pH of the environment. In addition, the fuchsin used in conventional reagents become unstable when exposed to heat, leading to a quick deterioration in the effectiveness of the reagents.
Thus, there is a need in the art for the development of a reagent that remains stable in heat and which test accuracy is less affected by the pH of its surroundings. By using a test solution containing a detection compound in the pararosaniline HCl family, which reacts to aldehydes by creating a solution of different color, which also exhibits stability towards heat and acidic conditions when stored, the shortcomings of conventional aldehyde test kits are overcome.